166 THE AMERICAN MONTHLY [May 



very few people who know how it should be carried out. 

 The cornea must be flattened, not left in the globular con- 

 dition of life. The simplest way to exhibit the effect is to 

 cut a cross out of brown paper, about %" long - , place this 

 on the mirror of the microscope and focus the facets of 

 the cornea in the usual way with a ^" objective. You 

 then — and this is the important stage on which the result 

 depends — gently rack the objective upwards, causing the 

 structure to appear to go out of focus, at the same time 

 moving the cross on the mirror by means of a pointed 

 stick of wood. It will be evident where it is best to stop 

 raising the objective, for the cross or the stick will be seen 

 in the facets. It then only remains for the cross to be so 

 set on the mirror that it appears in the centre of each of 

 the facets. There are many other ways in which the ef- 

 fect can be produced, a very pretty one being to throw a 

 brilliant light on the face of a friend who sits at the side 

 of the microscope, and so arranging the mirror that the re- 

 flection of his face falls upon it and is again transmitted to 

 the cornea. Also by a little scheming the second hand of 

 a watch can be seen in each of the facets. When well shown, 

 these experiments always create astonishment and inter- 

 est. A little practice soon enables one to do them with 

 facilitv- 



MICROSCOPICAL SOCIETIES. 



Quekett Microscopical Club. — 367th meeting Friday, 

 March 17, at 20, Hanover-square. Mr. Rousselet read a 

 paper on "Torchosphaera," an extraordinary rotifer, not 

 as yet found in England. This animal is a sphere of about 

 the size of Volvox globator, and two species are known, 

 one with the ciliary zone at the equator, thus dividing it 

 into two equal halves,and another with the zone nearer the 

 pole, which is thus unequally divided. The organs are 

 contained in the lower hemisphere, and very clearly visi- 

 ble. A mounted specimen was exhibited- under the micro- 

 scope. Mr. Soar read a note on a water-mite, a species of 

 atax, which he believed to be new. Mr. Lewis Wrig-ht, as- 



